CWE-526: Cleartext Storage of Sensitive Information in an Environment Variable
Official CWE-526 CWE context with Glexia analysis, remediation guidance, related CVEs, and ATT&CK context.
Glexia's Take
CWE-526: Cleartext Storage of Sensitive Information in an Environment Variable
Cleartext Storage of Sensitive Information in an Environment Variable represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.
Executive Impact
- Confidentiality: Read Application Data
Developer Pattern
CWE-526 is the kind of defect developers can usually prevent with explicit validation, safer framework defaults, and tests that exercise hostile input or unsafe state transitions.
Confidence
high confidence from CWE-526, 4.20.
Official CWE Definition
CWE-526: Cleartext Storage of Sensitive Information in an Environment Variable
The product uses an environment variable to store unencrypted sensitive information.
Information stored in an environment variable can be accessible by other processes with the execution context, including child processes that dependencies are executed in, or serverless functions in cloud environments. An environment variable's contents can also be inserted into messages, headers, log files, or other outputs. Often these other dependencies have no need to use the environment variable in question. A weakness that discloses environment variables could expose this information.
Developer And Remediation Guidance
How teams prevent and detect this weakness
Causes
- Missing validation
- Unsafe defaults
- Insufficient authorization or memory-safety invariant
Remediation
- Architecture and Design: Encrypt information stored in the environment variable to protect it from being exposed to an unauthorized user. If encryption is not feasible or is considered too expensive for the business use of the application, then consider using a properly protected configuration file instead of an environment variable. It should be understood that unencrypted information in a config file is also not guaranteed to be protected, but it is still a better choice, because it reduces attack surface related to weaknesses such as CWE-214. In some settings, vaults might be a feasible option for safer data transfer. Users should be notified of the business choice made to not protect the sensitive information through encryption.
- Implementation: If the environment variable is not necessary for the desired behavior, then remove it entirely, or clear it to an empty value.
Detection
- Automated Static Analysis: Automated static analysis, commonly referred to as Static Application Security Testing (SAST), can find some instances of this weakness by analyzing source code (or binary/compiled code) without having to execute it. Typically, this is done by building a model of data flow and control flow, then searching for potentially-vulnerable patterns that connect "sources" (origins of input) with "sinks" (destinations where the data interacts with external components, a lower layer such as the OS, etc.)
Mappings
Related CVEs, CWEs, and ATT&CK context
Related CWEs
ATT&CK Relevance
ATT&CK relevance is shown only when reviewed or responsibly inferred.